OLED lighting tile preparation on Gen2 deposition tool

OLED signage- and lighting tiles have been prepared on a Gen-2 OLED deposition tool. The manufacturing system combines high throughput with flexibility in production at highly-precise deposition conditions. It consists of different clusters including process modules for pre-treatment, organic layer deposition, metal deposition and automatic transfer to an encapsulation system. Five process modules for the organic and two for the metal layer depositions are available for preparation of OLED devices. The type of substrates used in this work is float glass coated with indium-tin oxide (ITO) and structured by screen printing processes. The substrate size is 370x470 mm2. There are 24 lighting tiles on each Gen-2 substrate. Active area of a single lighting tile is 38.4cm2. Basic device structure is a bottom emitting p-i-n-type architecture. This OLED device structure consists of a p-doped hole transport layer (p-HTL), an electron blocking layer (EBL), an emitter doped emission layer (EML), a hole blocking layer (HBL), a n-doped electron transport layer (n-ETL) and a metal cathode. The HTL and ETL are co-evaporated layers containing a host material and an electrical dopant. Monochrome orange p-i-n-type devices have been prepared. OLED parameter variation is discussed comparing tile-to-tile variation on the same plate and run-to-run variation on different Gen-2 plates. In general, several approaches can be chosen in order to realize white light emission. One promising approach is the stacking of two or three p-i-n units. The stacking of two and three p-i-n units, respectively, was investigated in order to evaluate a process enabling a device structure which is suitable for a lighting application. One unit contains the blue emission layer and the second unit contains the combination of orange and green emission layers in case of the 2-unit stack. Blue, green and orange units were stacked in case of the 3-unit device.